Brain tumors: criteria of response and definition of recurrence.

The criteria for determining response to therapy and establishing brain tumor recurrence are presented. Basing their conclusions on a series of more than 500 patients, the authors contend that serial scintiscans and computerized axial tomograms can be used to determine accurately the response to therapy and recurrence or tumor regrowth. The problems in evaluating response and tumor recurrence are discussed, with emphasis on those relating to concurrent glucocorticoid therapy and medical conditions such as infection, hematomas, and drug side-effects.